Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's added value is the disclosure that a request for a section returns that section plus its direct sub-sections – non-obvious behavior that affects how the agent should interpret the response. It does not say what happens for a non-existent or out-of-range rule number, which is the remaining gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the return-content definition before the usage instruction. The parenthetical example replaces what would otherwise take another sentence, so nothing is wasted.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter lookup with no output schema, the description gives enough to call it correctly and to anticipate the shape of the returned text. The only omission is failure behavior for an invalid or non-existent rule number, a minor gap for a read-only, idempotent tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the pattern already constrains the format, so baseline is 3. The description earns an extra point by explaining what the parameter value semantically pulls in (a numbered section plus its lettered children), which the schema's 'Número exacto' note does not convey.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Texto exacto de una regla') and defines scope precisely, including the hierarchical expansion behavior ('17.1' devuelve 17.1 y 17.1a–17.1e). The worked example makes it immediately distinguishable from the sibling search_rules, which searches rather than retrieves exact text.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly names the situation ('Úsala tras search_rules') and the alternative ('o cuando el jugador cite un número'), so the agent knows both when to call it and which sibling precedes it. No exclusions are stated, but the routing against search_rules is unambiguous.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.